1. Field of the Invention
The invention relates to a butt joint of wooden construction components such as solid wood frame components joined together with contact surfaces, with at least one connection element being designed symmetrical with respect to a center plane in about the form of a double dovetail-shaped wedge, or having some other undercuts. Bridging the plane of contact between the wooden construction components, the connection element engages grooves adapted to the cross sections of the connection element extending on both sides of the center plane. The grooves are open toward the same side edges of the wooden construction components. In particular, the invention relates to a post-and-lock joint, for example in conjunction with light framework constructions.
2. The Prior Art
A butt joint of the type specified above is disclosed in French Patent No. FR-A-1 338 198. This patent shows a long-stretching connection element received in receiving grooves extending from the contact surfaces of joined frame components into the components, bridging the plane of contact. This connection element is designed symmetrical with respect to a center axis falling in the plane of contact of the joined frame components. Spaced from the center axis, the connection element has thickened or hammer head-like sections, which engage correspondingly shaped widenings of the grooves, which taper toward the contact surfaces of the frame components, thereby providing for a form-locked connection of the frame components.
This known butt joint has been successfully used for the assembly of small construction components such as in the manufacture of furniture. However, it has the drawback that forces attacking in the direction of the longitudinal expanse of the connection element cannot be absorbed. Furthermore, the connection elements may become loose in the course of time depending on the weather conditions. This loosening can only conditionally be countered by increasing the press fit of the connection elements in their receiving grooves, because when the connection elements are driven into the grooves, this may easily cause the grooves of the construction component to be torn out.
It is therefore an object of the invention to provide a butt joint of construction components, in particular of frame components, which is capable of transmitting forces acting in the direction of the longitudinal expanse of a connection element without problems. In the present case, the term xe2x80x9cconnection of frame componentsxe2x80x9d is understood to include post-and-lock bolt connections as well.
This object is accomplished according to the invention with a post-and-lock bolt joint, comprising at least one connection element which is designed symmetrically with respect to a center plane in about the form of a dovetail-shaped double wedge, or which has other undercuts. The connection element engages grooves which are open toward the contact surfaces and are adapted to the cross sections of the connection element extending on both sides of the center plane, bridging the plane of contact between the wooden construction components. The grooves are open toward the same side edges of the wooden construction components. The butt joint is secured by at least one long-stretching second connection element which bridges the plane of contact between the wooden construction components and is received in sections of the construction elements and at the same time penetrates the first connection element transversely.
The first connection element provides for a form-locked connection between assembled frame components or other wooden construction components and is therefore itself fixed in its position in a form-locked manner by the second connection element penetrating the first connection element. Loosening of the first connection element and thus loosening of the butt joint is consequently excluded.
Furthermore, the butt joint as defined by the invention satisfies static requirements in that forces acting between the assembled wooden construction components in the direction of the longitudinal expanse of the connection element can be absorbed. The novel type of butt joint is therefore useful to applications that were not previously accessible to known butt joints of the type explained above, such as post-and-lock constructions such as glass-enclosed attachments in the form of winter gardens, or porches, where the wind pressure loading the framework fillings has to be transmitted from cross or secondary supports connected to the posts, the so-called lock bolts.
The second connection means penetrates the first connection element in an inclined manner relative to the plane of contact between the assembled frame components, and extends into the frame components and through the first connection element with an acute angle of preferably 45 degrees versus the plane of contact.
The second connection element may be a pin received in slanted bores which are located in sections of the frame components that are arranged adjacent to each other in the plane of contact, and which extend through the first connection element. The pin is secured in its installed position by suitable means. In particular, the pin forming the second connection element may be received with a press fit at least in one of the slanted bores extending in the frame components.
In an alternative embodiment of the invention, the second connection element may be an inclined nail driven into one of the wooden construction components, for example at an angle of 45 degrees in relation to the plane of contact. The nail, bridging the plane of contact, penetrates the first connection element and projects up into the second wooden construction component.
The use of screw nails as second connection elements has been found to be especially advantageous because such screw nails are capable of withstanding much greater pull-out forces than conventional nails with smooth shafts.
Instead of using a pin received in an inclined bore, or a driven-in inclined nail, it is possible to employ a safety screw as the second connection element. The safety screw is screwed into the assembled wooden construction components inclined in relation to the plane of contact between the assembled wooden construction components, with full penetration of the first connection element. A butt joint produced with the use of such a safety screw satisfies particularly high static requirements.
The safety screw preferably has a thread section equipped with a self-cutting thread. This thread section may be adjoined by the thread-free section of the shaft which, in the screwed-in condition of the safety screw, penetrates the first fastening element crosswise and secures it in its position in this way.
According to a preferred embodiment of the invention, there are at least two long-stretching second connection elements, which are arranged at an angle of preferably about 90xc2x0 in relation to one another. This creates a butt joint that satisfies even higher static requirements. Such a butt joint can be stressed not only by forces directed perpendicular to the axis of the wood construction component, (which is preferably in the form of a secondary support or lock bolt), i.e. by transversely acting forces, but also by forces acting in the direction of the axis of the wooden construction component, and thus by tensile forces without resulting in loosening of the connection elements over the course of time. Furthermore, it is then no longer necessary to pay attention to the exact position of the components when they are installed.
It is useful in this connection if at least two of the long-stretching second connection elements are arranged so that their longitudinal axes are substantially disposed in one common plane.
Preferably, at least two of the second connection elements are arranged symmetrically in relation to a longitudinal axis of the first connection element, and/or in relation to the plane of contact and/or its normal.
By virtue of the measures described above, the acting forces can be favorably transmitted to the adjacent wooden construction component irrespective of the position in which the connected wooden construction components are installed. Cross forces, if any, i.e. forces acting perpendicular to the longitudinal expanse of the connection element, can be safely trapped in both directions.
The measures described above contribute both individually and in combination to a butt joint of construction components that is capable of transmitting forces acting in the direction of the longitudinal expanse of a connection element without any problems.